The calculation of parton distribution functions (PDFs) using lattice QCD is hindered by their definition, which involves fields separated along the light cone. In the last few years, there has been increased interest in methods for circumventing this problem and obtaining PDFs from calculations in Euclidean space. One such approach involves calculating so-called quasi-PDFs, which are defined using nucleon matrix elements of a nonlocal operator. A conceptual issue in this approach is how to renormalize the nonlocal operator. It will be shown that this problem can be simplified by introducing an auxiliary field such that the nonlocal operator can be replaced with a pair of local operators in an extended theory. The effect of nonperturbative renormalization on matrix elements used for computing quasi-PDFs will also be shown, as well as initial steps toward studying the continuum limit.